--- In [email protected], "pavoturkey" <[EMAIL PROTECTED]>
wrote:
>
> I have embedded an IE WebBrowser control inside a windows C# form. I
> am using the WebBrowser control to load in an svg document. I was
> wondering if there is any way to register methods in my C# form to the
> svg document events? I want to be able to listen to svg "onmouseclick,
> onmouseover, etc." events occuring within the svg document in my
> WebBrowser control and trigger a method call present in my C#
> application. Does anyone know if this is possible or if you have had
> success implementing something of this nature? Thanks.
>
Yes this is possible. I have been working on something very similar
in Delphi for the past while and have finally gotten it working! I
have an html file that defines an embedded svg file which I load into
the Webbrowser control (EI6 with ASV3.03) on a form. Then I hook up
event listeners to capture click events.
The first confusing part was the fact that you must wait until the
browser control finishes loading the file (which happens async) before
you can get at the svg file. Use the DocumentComplete event of the
browser control for this.
Once the document is loaded you can get a reference to the html
document in the browser using the browser.document property. Then you
can use the html dom to get a reference to the svg document using the
'embeds' property and the 'getSVGDocument' method. Note that .NET has
no idea what objects/methods are available in the dom so you have to
use reflection to get the object types and InvokeMember to call methods.
Now that you have the svg document you can use svg dom methods (via
reflection) to capture click events. The dom addEventListener method
takes three arguments: 1. The name of the event you wish to capture -
in this case 'click' 2. The object that handles the event - in this
case it will be the .NET form that contains the browser control 3. A
boolean flag to indicate if the event should continue to bubble up -
normally false unless you have multiple event handlers. These three
parameters need to be put into an object that can be passed in the
InvokeMember call. I made myself a record of the type 'object array'
which could hold the parameters and then just passed the record into
the invoke of the addEventListner.
The only remaining part is the actual event handler. Define a
function on the browser form like this: 'handleEvent(evt: TObject)'.
This function acts as a delegate and will end up getting called
whenever a click happens. The parameter of the event is an object
that is the svg shape that was clicked on. Once you have the object
you can do whatever you like with it - such as get its ID or name.
One other thing that I found really confusing at first was that the
svg dom is case sensitive and you must follow the odd capitalization
exactly or the functions won't get called properly.
Hope this helps, Wayne
---
Code Samples:
---
This is the record to hold the parameters for addEventListener.
type ThreeParam = array[0..2] of TObject;
---
This is the code to hook the form up as the handler of svg events.
var
params3 : ThreeParam;
HTMLDocument : MShtml.IHTMLDocument2;
SVGViewer : TObject;
SVGDocument : TObject;
SVGRootElement : TObject;
begin
try
// The following snippet can be used in the
"AxWebBrowser1_DocumentComplete" event of an embedded
// webbrowser window to obtain a reference to a SVG document
that had been loaded into a web browser's
// ASV plugin.
// The webbrowser has just finished loading the basic html
document which embeds the SVG shell.
HTMLDocument := Self.AxWebBrowser1.Document;
// Get a reference to the SVGWindow, SVGDocument and the
RootElement.
SVGViewer := HTMLDocument.embeds.item('svgShell',0);
SVGDocument := SVGViewer.GetType.InvokeMember('getSVGDocument',
BindingFlags.InvokeMethod, nil, SVGViewer, nil);
SVGRootElement :=
SVGDocument.GetType.InvokeMember('rootElement',
BindingFlags.GetProperty, nil, SVGDocument, nil);
// Add the Event Listner here.
params3[0] := TObject('click'); // The event will be the mouse
click event.
params3[1] := TObject(Self); // This form will be the object
that catches the event.
params3[2] := TObject(false); // Event bubbling is false.
// Run the addEventListener method of the rootElement to have
this form start listening for clicks.
SVGRootElement.GetType.InvokeMember('addEventListener',
BindingFlags.InvokeMethod, nil, SVGRootElement, params3);
except
Debug.Write('Cannot add event listener.');
end;
end;
---
This is the code that actually receives the click event.
procedure TSVGMapWindow.handleEvent(evt: TObject);
var
targetElement : TObject;
begin
if Assigned(evt) then
begin
targetElement := nil;
try
// Make sure we have a valid event and can get at the
targetElement of the event.
targetElement := evt.GetType.InvokeMember('target',
BindingFlags.GetProperty, nil, evt, nil);
except
Debug.Write('No target for this event.');
end;
end;
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